1. Field of the Invention
The present invention is directed to a triple reduction final drive assembly for a work vehicle which is both compact and relatively inexpensive to manufacture.
2. Description of the Prior Art
Work vehicles are typically powered by an internal combustion engine that drives a transmission. The rotating output of the transmission is directed to the drive wheels or sprockets by a final drive assembly. Typically the final drive assembly includes a gear reduction which reduces the speed applied to the drive wheels or sprockets and increases torque, thereby lowering stress and simplifying the transmission. Three major types of final drives that offer gear reduction are pinion final drives, planetary final drives and chain final drives.
In a pinion final drive, a pinion gear operatively engages the transmission output shaft and drives a larger spur gear, thereby reducing the output speed of the spur gear and increasing torque. Additional pinions and spur gears can be added to increase the gear reduction function, but this requires increased space and cost.
Planetary final drives are more compact than pinion final drives resulting in a greater gear reduction in a smaller package. However planetary final drives are more costly to manufacture.
Chain final drives result in the most clearance over pinion and planetary final drives, but have a tendency to loosen due to wear and stretching.